Gyroscopic stabilizing apparatus



Feb. 19, 1952 A. w. KUYVENHOVEN GYRoscoPIc STABILIZING APPARATUS 6 Sheets-Sheet l Filed Deo. 27, 1945 ATTORNEY Feb. 19, 1952 A. w. KuYvENHovEN GYRoscoPIc STABILIZING APPARATUS 6 Sheets-Sheet 3 Filed Dec. 27, 1945 INVENTOR BY Q mld* R im ATTORNEY Feb. 19, 1952 A. w. KUYvENHovEN 2,586,469

GYROSCOPIC STABILIZING APPARATUS Filed Dec. 27, 1945 e sheets-sheet 4 INVENTOR ATTORNEY Feb. 19, 1952 A. w. KuYvENHovEN 2,586,469

GYROSCOPIC STABILIZING APPARATUS Filed Dec. 27, 1945 6 Sheets-Sheet 5 ATTORNEY INVENTOR f 6 Shee\tS-Sheeb 6 Filed Dec. 27, 1945 hun INVENTOR m95 MW,

Y Y ATTORNEY Patented Feb. 19, 1952 GYROSCOPIC STABILIZING APPARATUS Arend Willem Kuyvenhcven, Richmond, England, assignor to Brevets Aero-Mecaniques, S. A., Geneva, Switzerland, a society of Switzerland Application December 27, 1945, Serial No. 637,439 In Great BritainMarch 16, 1943 Section 1, Public Law 690, August 8, 1946 Patent expires March 16, 1963 The invention relates to gyroscopic apparatus of the kind employed for the ,stabilization of gun mountings, directors, sights, searchlightsl or the like (hereinafter referred to generally as controlled apparatus) mounted on ships, aircraft, tanks or other moving bodies, whereby such controlled apparatus is caused to maintain an angular disposition in space which is independent of the angular movements of the moving body occasioned by roll, pitch, yaw or change of course.

The term controlled apparatus is intended to include any piece of apparatus having an axis (such as the line of fire of a gun, the axis of a searchlight beam vor the line of sightaof a director or sighting device) which is required to be stabilized and, in general, to be capable of orientation in space; this axis will be referred to generally as the principal axis of the particular piece of controlled apparatus.

The main object of the present invention is the provision, by the use of a pair of gyroscopes, of stabilized horizontal and vertical datum planes with respect to which the principal axis of the controlled apparatus may be given elevational and training movements; the invention is thus to be distinguished from known apparatus Yin which the principal axis is stabilized by keeping it parallel with the axis of a single free gyro, which provides no such datum planes.

In a broad sense, the invention is concerned with gyroscopi'c stabilizing apparatus of the nonpendulous type, and comprising a first gyroscope providing a horizontal plane datum, a gimbal frame member supporting said rst gyroscope, a second gyroscope gimbal mounted on said frame member to provide a vertical plane datum, said second gyroscope with its gimbal mounting forming a subsidiary non-pendulous system rotatable about the line of the spin axis of said first gyroscope, torque motors connected to bring about precession of said gyroscopes and vertical sensitive elements for controlling the operation of said torque motors to maintain the spin axis of said first gyroscope substantially vertical and to maintain the spin axis of said second gyroscope substantially horizontal.

The stabilizing movements are preferably given to the controlled apparatus with respect to the moving body by power units operated from transmitters whose outputs represent the instantaneous angular displacements between the horizontal and vertical datum planes provided by the stabilizing apparatus and planes or axes fixed with respect tothe moving body and particil Claims. (Cl. i4-'5.34)

Wpating in its angular movements (such as the deck plane and fore-and-aft line of a ship).

By the term torque motor in the preceding paragraph and the claims is meant a device comprising a stator and a rotor between which unlimited relative rotational movement is possible, and between which a torque can be produced which is independent of the degree of the said movement. Alternating current induction mo- Itors, working either from a three-phase supply solenoid with an armature, in which only limited relative movement is possible and the force applied vares with the extent of the said movement.

In the application of the invention to various gunnery problems it is frequently necessary to convert stabilizing impulses provided by the stabilizing unit with respect to one set of axes into corresponding impulses with respect to another set of axes. For example, in a fire control system incorporating a director or sight and a gun the principal axes of the sight and the gun differ by the quantities known as lateral and vertical deflection, so that if the stabilizer is carried on the director and used directly to stabilize the sight, corrections have to be applied to the stabilizing impulses to effect the correct stabilization of the gun. One way of effecting such corrections depends upon the use of corrector units as hereinafter described; such corrector units, however, generally employ complex systems of solid cams, and it is a further object of the present invention to minimize the use of such units by incorporating a resolving mechanism directly with the stabilizing unit.

Accordingly, a stabilizing unit according to the invention may be mounted within a further gimbal system adapted to resolve the stabilizing impulses provided by the said unit into corresponding impulses with respect to a system of axes different from that system of axes with respect to which stabilizing impulses are given directly by the unit itself.

Reference will now be made to the accompanying drawings, in which:

Figure 1 is a perspective and largely schematic view (with parts cut away for clarity of illustration) vof a complete stabilizing unit;

Y Figure 2 is a diagram illustrating the application of the unit shown in Figure l to a control system;

Figures 3 and 4 are circuit diagrams of alternative switch and torque motor combinations.

Figure 5 is a view similar to Figure l of the stabilizing unit combination with plane conversion resolving mechanism;

Figure 6 is a diagram illustrating the application of the unit shown in Figure 5 to a gun con- Y trol system;

Figure 7 is a View similar to Figure 5 of a stabilizing unit combined with an alternative ar.- rangement of resolving mechanism;

Figure 8 is a diagram illustrating the application or' the unit shown in Figure 7 to a particular gun control system;

Figure 9 illustrates a modified application of the unit shown in Figure l to a biaxialdirector.

Referring to Figure l, the roll gyro has. aspin.

non-pendulous combination (apart from. the.

optionall addition of a latitude rider. I iltas hereinatter described).

Since the spin axis of the roll gyro will. tend to remain vertical, rolling and pitching motions of the moving body will result in relativel movements (l) between the xed brackets BI and the frame F2, and (2) between the frames FZand FI.

These relative movements are respectively im-` parted (l) through gearing WTI to a pair of transmitters TI, and (2) through gearing WT2 to a pair of transmitters T2. The two transmitters of each pair provide-for ne and coarse control in known manner, and for purposesof description may thus be regarded as a single transmitter. These transmitters formY part of any. convenient electrical or mechanical systems for the systems for the transmissionv of angular indications, and.

it is clear that by coupling thernto power followup devices incorporated in controlledapparatus having a system of relatively movable parts geef. nietrically similar` to that of the gyrov unitvde.-

scribed, a given axisA on the controlled apparatus (corresponding with the gyrc spin axis) can ,be caused to remain substantially vertical-.notwithstanding therpitching and rollingmotions of the moving body.

With such an arrangement, however, small torques are continually being applied. to the gyro by the friction of the bearings, the slight load imposed by the transmittersTI and T2, andy any small lack of true balance of the system as a whole. These torques and the appropriate component of earth rotation would, if` uncompensated, result in a precession of the gyro which would cause its spin axis (and consequently the corresponding axis of thecontrolled. apparatus) to stray from the true vertical axis A3. By the use of precessing torque motors with verticalsensitive control, however, such strayingis coniined to very small limits.

A pair of mercury switches MSI, MS2 are mounted on the frames F2' and FI respectively. The switch MSIl controls a split-phase induction torque motor TM2 in eitherone of the ways hereinafter more particularly described with reference to Figures 3 and 4, the arrangement being such that this motor will apply a torque to thev frame Fl (via gearing WMZ) whose direction depends upon the direction in which the switch MSI is tilted. If, therefore, the frame F2 tilts in a given direction with respect to the vertical, the switch MSI will operate toenergize the. motor TM2,v and the resultingtortureY applied by this motor is arranged to be such that it will cause the gyro to precess in the direction necessary to restore the frame F2 and hence the switch MSI to their neutral position. The switch MS2 is connected in a similar manner to a torque motor TMI which operates through the gearing WMI to apply a torque to the frame F2. If desired the switch MSI may be mounted on the frame FI provided that'ts operative axis is correctly positioned.

The two; control systems thus operate between them to prevent the spin axis of the gyro from ever departing from the true Vertical axis A3 by more than a limited amount, which by suitable design of the switching system may be made very small. It will be appreciated, however; that from the point of view of' stabilization the actual departure of the spin: axis from the vertical (within the limits imposed by the design, of the, ap-l paratus) may berofl less importance than its rate of angular movement with respect to the'vertical, which should be kept as low as possible. For this purpose rheostats are inserted into. the circuits of the torque-motors TMI and TM2, and are ad.- justed to give torques just sufficient to overcome the disturbing forces referred to above. Thevalue of these-torques maybe-suiiiciently'low to correspond witha precessional ratek ofjthel order of d5 per second, the maximum error iny angular velocity in the output of thetransmitters TI`A and T2 under all conditions.

The value-of using torquemotorszinaccordance with the invention will be. appreciated in this connection, since they` provide aitorque, whichis independent ofthe relative displacement between rotor and stator;

The yaw gyro hasahorizontal spinaxis A5 and is mounted-ina casingGZ pivoted about a horizontal axis A4 at; right angles to the spin axis within a gimbal frame F4; this inl turn is pivoted about thefvertical axis A31' within theframe FI previously referred.` to.` The yaw gyro and the casing G2 are also non-pendulous (apart from the optional addition of a` latitude rider LY as hereinafter described) Since the spin axis; A5' ofi thel yaw gyro will tend to remainA in aparticulan azimuth, a yawing motion or, changel` of. course, oi the-moving body will result in a. relative. movementk between the frames F4 and FI.. This relative movement is imparted through gearing WTS to a transmitter T3 similar similarlyv coupledto a power follow-upgdevice for effectingthe.stabilizationoi the. controlled appa-- ratus in azimuth.

Friction and the smallload vci: the transmitter T3 will4 producel a torque about the vertical axis, A3 such asitoJ maker-the gyro precess aboutV the` pivotal `axisfflli of the-casing Gland it is thereiorenecessary toV applyy a` correcting, precessing torque to maintain the spinl` axis Aoi"4 the gyro in an approximately-horizontal plane.. For this purposea mercuryswitch MS3is associated with the casingv G2 and is coupled as previously describedto a torquev motor TM3 cooperating with gearing WM3. This motory is arranged, by ad-Y justment of avrheostat, to produce. (when ener.- gizedby the operation.- of themercuryY switch) a torque which just overcomes the maximum valuel which Will'. therefore represent' to the. transmitters TI and T2, andl of the disturbing torques referred to above, thereby precessing the gyro back so that the mercury switch MS3 breaks the circuit. The spin axis A of -the gyro will thus hunt continuously about a mean horizontal position, from which it will never depart by more than a very small angle determined by the design of the switch system. Electrical connections to the yaw gyro and switch MSS are effected through suitable slip-rings J.

Meanwhile, friction in the horizontal trunnions of the casing G2 during the very small hunting movement referred to above, any slight lack of true balance of this easing, and the component of the earths spin about a vertical axis will all result in a very slow precession of the yaw gyro about the vertical axis A3, this gyro thus being of the type known as a slow wanderer. Regarded as an azimuth datum, however, the actual position of the spin axis does not matter in many applications provided that at any instant its rate of precession in the horizontal plane is suiciently small.

If desired. instead of making the yaw gyro and its casing G2 strictly non-pendulous, a latitude rider LY may abe located on the casing so as to produce a torque about the axis A4 and hence a uniform precession about the axis A3 which, by adjusting the weight or position of the rider in accordance with the latitude, may be made to compensate exactly for the effect ofthe earths rotation. This eliminates the most important factor leading to slow wander of the yaw gyro.

In some applications it may be desired to make the yaw gyro north-seeking, so that i-t provides an invariable azimuth datum. This may readily be done by providing a torque motor TM4 which is adapted to apply a torque to the casing G2 about the axis A4 and is energized by misalignment between the transmitter T3 and a transmitter operated by the ships gyro compass, thus causing very slow precessions about the axis A3 to keep the spin axis of the yaw gyro from departing from the true meridian by more than a very small amount. This arrangement provides an azimuth datum which incorporates both the north-seeking property of the compass and the very small precessional rate obtainable with the yaw gyro, a rate which is much smaller than that of the gyro compass itself.

The accelerations due to change of course and change of speed of the ship, which cause unidirectional forces to be applied. to the system, affect only the mercury of the mercury switches, as .the gyro arrangement is non-pendulous. For accelerations over a certain magnitude the mercury will therefore move away from its central position, make contact, and, if no device for switching oi the torque motors during change of course and speed has been fitted, start the yappropriate gyro toA precess. The rate of precession is restricted by the setting of the resistance value in the particular torque motor circuit, and the precessional rate under all conditions of ship movement therefore cannot exceed lthe set value (say 0.5' per second for the roll gyro). The amplitude of error depends upon the duration (not the magnitude) of these unidirectional accelerations (in seconds l5 0.5=7.5 for the roll gyro).

The effect of earth rotation on the yaw gyro (which can produce a maximum wander of 0.25' per second) may, as previously described, be substantially eliminated by the use of a latitude rider, in which casethe precessional rate may be -made appreciably lower than 1n the case of the roll The angular momentum of a gyro is directly proportional to its speed. The precessional rate produced by the torque motors is therefore inversely proportional to the gyro speed. When starting up the system, the torque motors will,

during the running up of the gyro wheels, pull the system quickly into the erected position, no matter what the initial position of the non-pendulous system may be.

Since the roll gyro provides a horizontal plane and an axis A3 at right angles to it about which v the frame F4 containing the yaw gyro rotates, horizontal and vertical datum planes are provided which, whatever the angular deviations of the system may be, will at all times remain at right angles to each other and to which, if this arrangement is used as a datum for measuring rates of a target, the angular movements of the target are also referred. These lateral and vertical target rates will therefore now represent the true rates of the target unaffected by roll rates, and they are at all times measured at right angles to each other.

Figure 2 illustrates schematically the application of the invention to a gun control arrangement, which will now be described.

As shown in Figure 2 a gyroscopic stabilizing unit-| according to the invention (hereinafter referred to as a stabilizer) is mountedv on a training base 2, which also carries the gun pedestal 3. pivotally mounted on the pedestal 3 about. an axis Xl parallel with the axis AI of the stabilizer.

The transmitter Tl (corresponding with the pair of transmitters TI in Figure 1) is wired to a motor MI which rotates the cradle 4 about the axis XI, the arrangement being such that any rotation of the transmitter rotor from a datum position causes the motor to operate in the appropriate direction. A second transmitter Rl is connected in the circuit in such a Way that its output combines differentially with that of Tl, and the rotor of RI is connected mechanically to the motor MI; The transmitter RI thus acts as a resetter, any angular displace-A ment of the rotor of TI causing MI to operate until it has moved the rotor of RI through the same angle (in the opposite sense electrically); when this occurs MI is again brought to rest, having copied exactly the movement of the rotor of Tl. For convenience of illustration the wir.- ing is indicated by a single wavy line, the whole arrangement being illustrated schematically and being capable of taking various forms, all of which will be familiar to those skilled in the art. A similar convention is used throughout all the figures in which similar transmission systems are illustrated, transmitters which are shown as being connected in series in a particular line being arranged so that their outputs are added differentially to those of other transmitters in the same line.

ate to give the cradle 4 movements relative to A cradle 4 carrying the gun 5 is ther base; similar# to those of the;A fratrie,r F2;

thaxisrXZ ofthe gun. trunnionawill thus be kept'fhorizontal. andA parallel. withpthev axis: A2. For-stabilization. about the.Z axisX2, the'transmitter-TZiSzcOnnected in the manner4 previously described to the elevating motor M2v and resetter R2,.the arrangement sov far; described thusl stabilizing the: gun completely: as regards. rolland pitch. Transmitters 6 and I may addl in,

quantities 'suchasf generated elevation rate and verticali deflection, derived: from otherY parts. ofv

theA motor M13 affects the stabilizer as well as;

the gun, no separate resetter, isv required, rotation` of the. whole stabilizer automatically` restoring, the'initial relative position of rthe rot-or andi stator of the transmitter T3. t may also be noted.. that a given relative angular displacement. between theV transmitter rotor and stator will in general require a1 somewhat different angular displacement of the training base 2 for exact. restoration, since the former displacement takes place about the vertical` airisV A3 and the latter about the axis X13 perpendicular to the deck plane; the motor MIS will operate until thesaidrestoration is actually affected, however, irrespective of the angular movement of the training base required to achieve this. The difference between.. the displacements about the axes A3; and X13 is known. as the decir training correction, and the automatic: inclusion of this correction withoutv the necessity for separate calculating apparatus is an important feature of the present invention. As in the elevating system, further transmitters 8 and Q may add in other calculated: quantities such as generated training rate and lateral deflection,

The arrangement described with reference to Figure 2 is obviously equally applicable to the stabilization of other forms of controlled apparatus; the gun shown in Figure 2 could, for example, be replaced by a director. The invention may also obviously be usedV to provide stabilized platforms on which any desired piece of apparatus may be mounted.

As regards the transmission of datafrom the stabilizer to the controlled apparaus the invention is not conned to any particular form of transmission system; as analternative to systems of thel types hitherto described hunter transmission may, for example, be used, the appropriate part of the gyro system constituting the sensitiveelement andY cooperating with a followup element through a direct system of contacts. an electromagnetic pick-up arrangement, or a sensitive hydraulic valve;

Two alternative ways of operating the torque motors TMI, TMZ from the mercury switches MS2, MSI respectively in Figure 1 will now be described with reference to Figures 3' and 4.

Figure 3 shows one possible circuit arrangement of the switch MSI and associated apparatus, the arrangement in the case of the switch MS2 being similar. The switch` MSI comprises a small quantity of mercury (not shown) in permanent contact with an electrode 4I and adapted to make contact with either one of a pair of further electrodes 42, I3`V in accordance with the direction in which the switch is tilted with respect tothe vertical. The switch MSI controls the split-phase induction motor TM2,

the arrangement being; such: that thisl motor-will.. apply a torquek to the frame FI (via-.gearing in the motor; a rheostat 4l is includedk in. thecircuit for the purpose specied in the description of Figure l. IL therefore, the frame F2 tilts in a given direction with respect to the vertical, the switch MS I` will operatetoy energizevr the'rnotor rDMZ and theresulting torque-applied;

by this motor is arranged to besuch thatitfwill cause the` gyro to precess in the directionl necessary to restore the frame F2 and hence' the; switch MSI to their. neutral position. The'switcli; MS2 is connected in a similar mannerto at torque motorTMI which operates through the gearing WMI to apply a torque to the frame F2; If desired the switch MSI may be mounted on the frame FI provided that its operativev axis is correctly positioned. Switches o the kind described can bev designedv to operate for a displacement of thev order o- 2 or 3 in either direction from the neutral position.

Figure 4 shows an alternative circuit arrangement in which. the electrode d3, in the switch MSI.V is eliminated, the electrodesJlIl and 42; being connected inv circuit with an, alternating, or direct current supply 49 and the windingk 5030i a: relay. 5I. When the switch MSI is open a. spring 52- causes the contact arm 53 of therelayxtoengage a contact 54, While when the switch is.,closed the relay operates to bringv the arm 53 into; engagement witha contact 55. The members 53,54, 55 thus replace the members 4|, 42, 43 of Figure 3,: the remainder of the circuit being identical.I This arrangement has the advantages (al that the currentthrough the mercury switch can be made smallerv than in the case, of Figure 3 andv (b) that the switch does not need to be` soA accurately made, since a. simple make and break of the switch effects an: instantaneous reversal of torque.. As` in the. case of Figure 3, a similar arrangement is provided with respect to the. With` this.

switch MS2 and. torque motor TMI. arrangement an accuracy of` the order of 10.5. can be obtained.

The. invention is not confined to the` use of mercury switches, as any suitable gravity-sensitive .switch ofA comparable sensitivity couldy be..

used.. Alternating current. induction motors are; as previously stated, the vpreferred form of torque-- motor, since they have no brushes and therefore oier little friction. Any. other typeotorque motor may, however, be used, particularly inconjunction with the relay arrangement shown in Figure 4, since the relay can have any number of contacts for reversing the torque;

Meansfor effecting .stabilization of apparatus about axes dilerent from those of the stabiliser itseliwill now be described..

Considering the unit shown'in Figure 1 it has been seen that any piece of controlled apparatus pivotally mounted about axes parallel with theaxes AI: 'and A2A canbe stabilized directly by irn-` parting to the appropriate parts of the mountings, through power motors operated by. the respective transmitters, movements equal and'i opposite to those imparted to the-said transmitters. If, however, the pivotal axes of a particular piece of controlled apparatus are not parallely with the i axes. AI- and, A2, then either (1.) the impulses from the transmitters TI and T2 must be suitably transformed by a corrector unit, or (2) the relative movements of the stabilizer unit must be expressed directly in terms of component rotations about a new set of axes parallel with the axes of the said piece of controlled apparatus.

One form of apparatus operating according to the second of these alternatives is illustrated in Figure 5. The unit shown in Figure 1 is incorporated in toto, and its parts are indicated as far as is necessary by the same reference symbols; the slip rings J, latitude riders LY, LR and torque motor TM4 have been omitted for greater clarity. The base B is pivotally mounted on a base B' about an axis AI 3 which, when both bases are horizontal, coincides with the vertical axis A3. A motor SI3 adjusts the position of B with respect to B', and their relative displacement is measured by a transmitter TI3. The gimbal frame FI is pivotally connected at the top, about axis A3, with a gimbal frame F; this is pivotally mounted about an axis AI2 normal to A3 within an outer gimbal frame F6 which in turn is pivotally mounted about an axis AII normal to A12 within brackets B3 mounted on the base B. Relative movements between F5 and F6 are imparted through gearing WTIZ to a transmitter TI2, and relative movements between F6 and B are imparted through gearing WTII to a transmitter TI I. 'Ihe transmitters TII and TI2 thus provide stabilizing impulses with respect to the axes AI I and AI2 in exactly the same way as the transmitters TI and T2 do with respect to the axes AI and A2. A transmitter TO3l measures the angular displacement between frames FI and F5 about axis A3. The manner in which this apparatus is used will be understood from the example which will now be described with reference to Figure 6.

Figure 6 shows the application of the apparatus to a triaxial director 6I and a triaxial gunmounting 62 carried on separate training bases.

The director 6I comprises a sight 63 pivoted about an axis YI2 within a frame 64 mounted on a platform 65 which is itself rotatably mounted about an axis YI I on a pedestal 66 carried by the training-base 61; this base is itself rotatable about the axis YI3 with respect to the fixed structure 68 of the moving body. 'I'he pedestal 66 also carries a stabilizing unit according to Figure 5, which is shown conventionally as a box 69 with the various associated transmitters and the motor SIS in juxtaposition therewith.

The gun 10 is supported by trunnions having an axis X2 in a cradle 1I which is itself pivotally mounted about the axis XI on a pedestal 12 carried by the training base 13; this base is rotatable about the axis XI3 (parallel with YI3) with respect to the fixed structure 68.

The base B of the stabilizing unit -69 is secured to the pedestal 66 so that the axes AI I and AI3 are parallel with the axes YII and YI3 resspectively. The transmitter TII is wired to a motor DI I which adjusts the position of the platform 65 with respect to the pedestal 66, the arrangement being such that any rotation of the transmitter rotor from a datum position causes the motor to operate in the appropriate direction. A second transmitter DRII is connected in the circuit in such a way that its output combines diiferentially' with that of TII, and the rotor of DRII is connected mechanically to the motor DI I; the transmitter DRI I thus acts as a resetter in the manner previously described,

the m otor DII thus being caused to copy the movements imparted to the rotor of TII.

As a result of the stabilizing impluses from the transmitter TI I the motor DI I will thus operate to give the platform B5 movements relative to the pedestal 66 similar to those of the frame F6; the axis YI2 of the sight will thus be kept horizontal and parallel with the axis AI2. For stabilization about the axis YI 2, the transmitter TI2 is connected in the manner previously described to the elevating motor DI2 and resetter DRI2, the arrangements so far described thus stablizing the sight completely as regards roll and pitch. A transmitter 14 adds in the quantity generated elevation rate, which is derived from another part of the complete re control system.

Finally, yaw stabilization is effected by the transmitters TO3 and T3 and motor DI3, which rotates the whole training base 61 relatively to the deck. As axis AI is (as hereinafter described) trained on gun bearing, lateral deflection has to be wiped out by means of TO3 in order to produce yaw stabilization for the director. It is important to note that since the motor DI 3 affects the stabilizer 69 as well as the sight, no separate resetter is required, rotation of the whole stabilizer automatically restoring the initial relative position of the rotor and stator of the transmitter T3. It may also be noted that a given relative angular displacement between the transmitter -rotor and stator will in general require a somewhat different angular displacement of the training. base 61 for exact restoration, since the former displacement takes place about the vertical axis A3 and the latter about the axis YI 3 perpendicular to theV deck plane; as in the similar case discussed in connection with Figure 2, however, the motor DI3 will operate until the said restoration is actually effected, irrespective of the angular movement of the training base 61 required to achieve this. `A further transmitter 15 adds in the quantity generated training rate.

The sight 63 is thus given its stabilizingimpulses (apart from that for yaw stabilization) in terms of the axes AI I and AI2, these axes always being parallel with its own axes YII and YI2 respectively. Owing to the different training of `the gun the corresponding gun axes XI and X2 cannot also be parallel with AII and AIZ, but in accordance with the third aspect of the invention they are arranged to be parallel with AI and A2 respectively, thus enabling the gun to be given its stabilizing impulses (apart from that for yaw) with respect to the latter axes. Constructional considerations demand that yaw stabilization for both sight and gun shall be aifected by rotationof the heavy training bases 61 and and 13 about the parallel axes YI3 and XI 3 which are normal to the deck plane. The iirst requirement for gun stabilization must therefore be to adjust axis AI so that' it is parallel with the position that XI should occupy to give the gun its correct training. Now the angle between the vertical planes through YII and X I measured in a horizontal plane is known as the lateral deflection in azimuth, and this is calculated by another part of the fire control apparatus and fed to the transmitter 16. The impulse from TO3 controls the motor SI3, the transmitter 16 acting as a resetter in the manner previously described. Here it is important to note that T03, whose axis is vertical, always measures the angular displacement between AII 1l and AI about the vertical Yaxis A3, and although SIS is rotating yBI about the generally -nonverti- ,cal axis AI3, it will in any case always operate lto make 'the output of TO3 equal andoppcsite to that of T6, so lthat AI will be given the correct f --from the motor DI 3, and the combined outputs of TI3 and 'II are "therefore made to operate, in

ycorriunctio-n with a resetterRI-S, the motor MIS which adjusts 'the 'training base 'I3 about the laxis XIS; this results in -the correct positioning of fthe -axis XI, which -is now always parallel with AI. f'lo make X2 parallel with A2 it is now -nec- :essary only to operate the motor MI, Iwhich ad- :lusts the vcradle 'Ill with respect to the pedestal 12 about axis XI, -by means of the transmitter TI in vconjuction with a `resetter R I Finally, Ithegunl must be adjusted with respect to .the stabilized trunnion axis X2, the quantities which it-requires being (1) stabilization Iwith respect to axis A2, `v(2) vgenerated elevation zrate and 3) vertical deflection, i. e. the angle, measured in a vertical piane, between the line of :sight of Vthe director and the Aline of re =oi 'the-gun. yQuantities (l) and'(2) are supplied by transmitters yT2 and I4 respectively and quantityA (3) by a transmitter 18, thevoutputs of all three transmitters being combined to control the elevatingmotors M2 in conjunction with its V*resetter R2.

As an alternative Ato the lconstruction shown in Figure 5 the unit may be ldesigned in such a V-waytha-t the base B is adaptedfto be Yrigidly secured to 'the Vdirectorfpedestal 66 and the base VB trained relatively thereto by the motor SIS. In this case the sight axes YI I, YIZ in Figure 6 would :be kept `parallel to the axes A I, A.2 respectively; further, the deflection wipe-out provided by TO3 in the control system of the motor DI3 ywould no longer be necessary. VThe design Ishown in Figure 5, is, however, preferred owing to its greater constructionalsimplicity.

`Figure 'I illustrates an alternative form of stabilizer whose construction differs from that shown in Figure. 5 in the following respects. The brackets B3 between which the `frame Et is pivotedare mounted on the saine base Bas brackets B51, .the axes AI vand `AII now coinciding. The frame F5, instead of being pivoted directly within F6 as` in Figure 5, is pivoted-about axis AI2 within a. :iframe AFl which is itself rotatably mounted within F6 on ball'bearings 88; lit is thus capable -of rotation with respect to yF6 about an axis A23 which,pwhen the base B is in the horizontal posi- -tion shown, coincides with A3. Fl is adjusted Yrelatively toFS bya motor S23 operating through gearing :95 v.which engages teeth 9E on FI, while similar gearing 91 operates a transmitter T23 which measures the relative position of FS and ,Apart from lthe above `features and, of course-,the absence of T'I 3.andiSI3, the construc- .ftion corresponds 'exactly in essentials with that :0f Figure 5.

Figure 8 illustrates a speoiiic application of the stabilizer shown in Figure '7 to a combined tria-Xial director 6I and triaxial gun mounting 62; in this iigure given reference symbols have the same meaning as in previous figures. The basic difference from the triaxial combination Aof Figure 5 is that the gun and sight pedestals l2 and 6B are now mounted on a common training base 69, with the axes XI and YI I parallel to each other and to the combined axes AI-AII of a stabilizer according to .Figure '7 which is carried on the same base 89.

The gun cradle 1I is stabilized about axis Xl (parallel with AI-AI I) by the system TI-RI- MI; this makes axis X2 parallel with A2, and enables the gun I0 to be provided with generated elevation rate, vertical deflection and stabilization about X2 by the transmitters 14, It and T2 respectively operating the motor M2 and resetter R2. Gun stabilization, apart from yaw, is thus effected in terms of the axes AI and A2 as in Figure 6.

vConsidering now the corresponding -axes YII and YI2 `of the sight 63, -we have seen that YII,

'like XI, is made parallel to the common .axis

AI--AIL YI2 cannot in general, however, be parallel to A2, since rthe sight must be trained about axis Y23 relatively to the gun (as hereinafter described) to allow Ifor lateral deiiection. YI2 is therefore made Vparallel to AI2 which is itself made to diier in angular position from AZ, in the horizontal plane, by the amount of the lateral deflection; this is effected by the circuit 'Il--TO3-S23 ina manner which will be clear from a consideration of the analogous. circuit TO3-76-SI3 in Figure 6. (Note: two transmitters 16, coupled mechanically..are shown in Figure 8.) The manner in which YI2 `is made parallel to AIZ will be Vconsidered in the following paragraphs, but assuming that this is so it will readily be seen how the sight" is now stabilized about YII by the system TI I-DRI I- DiI and stabilized and adjusted about YIZ by the system IfI--TIZ---DRI2-DI2, generated elevation rate being added in by 'I4 as before. The axis Y23 is now parallel with A23.

As regards the training system, it is important that the training of the sight should'be accurate and independent of that of the gun. Since the sight is already carried on the training base 89, which is set in accordance with gun-training by the `motor MI3, it is necessary to wipe this out from the sight-training drive 94; this is done by connecting the drive 94 to the sight-training motor D23 through a diiferential 9|, lthe third member of which is connected Vto the motor MIS to provide a wipe-out drive. The sight-training system is thus rendered mechanically independent of any imperfections in the gun-training system.

The motor D23 and its resetter DR23 are connected to the transmitter T3, a wipe-out transmitter 92 connected to the motor MIB, a transmitter 'I5 giving generated training rate, and the' transmitters T23 and '16. The necessity for the wipe-out transmitter 92 arises from the fact that the output of the transmitter T3 includes gun-training as well as the stabilizing impulses (owing to the fact that -the stabilizer is carried on the base 89), and it is therefore again necessary to eliminate this from the sight-training drive; the transmitters T3 and `92 thus neutralize each otherelectrically as regards gun-training in the same way as the drive from'the motor MI3 through the differential 9| provides mechanical assenso 13 compensation for the fact that the sight is carrled on the base 89,

Finally, it is necessary to train the gun in accordance with the setting of the stabilized sight plus lateral deflection. The motor MI3 and its resetter RI3 are therefore connected to a transmitter 93 driven by the motor D23 and to the transmitter T23, the latter transmitter inserting lateral deflection as measured about axis A23, the axis about which the sight is in horizon. For low angle'work in which the target is v.always on the horizon, such as arises in the caseof a ship firing on another ship yor a shore target, a simplified application of the unit shown in Figure 1 to biaxial systems becomes possible, and such an application will now be described.

' vFigure 9 shows a unit I according to Figure 1 mounted on the same training base `6l as a biaxial sight 63, the axis YI of the sight now being made parallel with axis AI of the stabilizing unit. It is now required that the line of sight of 63 shall always be horizontal, and it is therefore kept parallel with A2 -by controlling the sight elevating motor DI with its rese'tter DRI by the transmitter TI, an additional tra-nsmitter |04 being included in the circuit for the purpose of adjustment and also for eifecting hand stabilization of the sight in the event of the stabilizer breaking down. Stabilization and control of the line of sight in azimuth is effected by controlling the training motor DI3 by the transmitter T3 and a transmitter 'I5 adding in generated training rate as in earlier applications. The sight 63 may obviously be replaced by a searchlight, rangender, radar aerial system or any other piece of apparatus having a principal axis which requires to be stabilized and trained always in a horizontal plane.

It is to be understood that although the Various Y transmitters and torque motors employed in the gyroscopic stabilizing units herein described are generally shown as being operated or operating through gearing, it may be preferable in some cases to connect their rotors directly to the members with which they are to cooperate, this arrangement being advantageous as regards the minimization of friction if other design considerations permit its adoption.

I claim:

1. In a gyroscopic stabilizing apparatus, a non-pendulous system comprising a first gyroscope providing a horizontal plane datum, a gimbal frame member supporting said first gyroscope directly by the spin axis member of said first gyroscope, a second gyroscope gimbal mounted directly on said frame member to provide a vertical plane datum, said second gyroscope with its gimbal mounting forming a subsidiary non-pendulous system rotatable about the line of the spin axis of said rst gyroscope, torque motors connected to bring about precession of said gyroscopes and vertical sensitive elements controlling the operation of said torque motors to maintain the. spin axis of said first gyroscope substantially vertical andto maintain the spin axis of said second gyroscope substantially horizontal.

2. In a gyroscopic stabilizing apparatus as set forth in claim 1, a mounting for said gyroscopes movable relatively to said gyroscopes about three mutually perpendicular axes, a. support for said mounting, means connecting said support and said mounting for relative pivotal movement about at least one additional axis, and electrical transmission means carried by said support and having outputs representing a resolution into -terms of component rotations of the relative position between the axes of said mounting and the parts carried thereby, and the set of axes of said support.

3. In a gyroscopic stabilizing apparatus, a system as set forth in claim 1, a mounting for said gyroscopes movable relative to saidA gyroscopes about three mutually perpendicular axes, first electrical transmission means having outputs representing the instantaneous angular displacements between said mounting andjsaid horizontal and vertical data; a further gimbal system freely mounting said unit; and second electrical transmission means for resolving the outputs. of said rst transmission means into corresponding outputs with respect to a pair of axes, one of which is kept parallel with one of the system of axes with respect to which the outputs of said flrst transmission means are given while the other of the said pair of axes is angularly adjustable relative to the iirst of the said pair, said gimbal system including a pair of rings relatively rotatable and lying in a single plane, :one of said rings carrying the other, and a base member having aligned pivotal mountings for one of said rings and for said unit.

4. In a gyroscopic stabilizing apparatus, a system as set forth in claim 1, and a mounting for said gyroscopes movable relatively to said gyroscopes only about three mutually perpendicular axes.

5. In a gyroscopic stabilizing apparatus, a system as set forth in claim 1, a mounting for said gyroscopes movable relatively to said gyroscopes about three mutually perpendicular axes, a support for said mounting, and means connecting said support and said mounting for relative pivotal movement about at least one additional axis.

6. In a gyroscopic stabilizing apparatus, a system as set forth in claim 1, a mounting for said gyroscopes movable relatively to said gyroscopes about three mutually perpendicular axes, and a support for said mountingy comprising a gimbal system providing freedom of movement for said mounting about three axes, all of which are movable angularly with respect to the axes of said mounting.

7. In a gyroscopic stabilizing apparatus, a system as set forth in claim l, a mounting for said gyroscopes movable relative to said gyroscopes about three mutually perpendicular axes, first electrical transmission means having outputs representing the instantaneous angular displacements between said mounting and said horizontal and vertical data; a, further gimbal system freely mounting said unit; and second electrical transmission means for resolving the outputs of said first transmission means into corresponding outputs wth respect to a pair of mutually perpendicular axes angularly movable relative to the system of axes with respect to which the outputs of said rst transmission means are given.

resenting the instantaneous angular displace- -ments between said mounting and ysaid horizon .tal and Vertical data; a further gimbal system treelymounting Ysaid unit; and second electrical ,transmission means for resolving the outputs of said 'first transmission-means into corresponding `outputs with respect -to a pair -of axes, one of which is kept parallel with one of the system of `axes with `respect Vto which the outputs of `said vfirst-transmission means are given While the other of the said pair of axes is angularlyadjustable relativeto Ythe first of the said pair.

9. In a gyroscopicstabilising apparatus, .anon- :pendulous system comprising a first gimbal frame pivoted on a normally horizontal axis, a second gimbal frame pivotedin .said rst ,gimbal frame on anormally .horizontalaxis .perpendicular to the pivotal axis of said .rst ,gimbalframaa 'rst gyroscope rotor journalled ena .normally vertical -spin 4axis in .said second gimbal iframe, a third Agirnbal frame pivoted in said second gimbal frame coaxially .with thespin axis of said first gyroscope `rotonafourth gimbal frame pivoted in said third lgimbal (frameon a normally horizontal axis, a second-gyroscope rotor journalled in said fourth .gimbal frame on a normallyrhorizontal spin axis perpendicular to the pivotal axis of said fourth ygimbal frame, vertical sensitive elements on said `Iirst,.second.and fourth gimbal frames and torque motors under control of said vertical sensitive .elements connected to act on said rst, second and-thirdgimbal Yframes to bring about precession of said gyroscope rotors to maintain the spin axis of said first gyroscope rotor substantially vertical yand the -spin axis .of said second gyroscope `rotor substantially horizontal.

10. In a gyroscopie apparatusanarrangement as set forth in claim 9, a rotatable base member pivotally supporting said system by said vfirst gimbal frame, a xed base member -on which said rotatable base member is rotatable about an -axis which when Vertical is aligned with thespin axis of said first gyroscope rotor, a fifth -gimbal frame surrounding said system and pivoted on a normally horizontal axis to said fixed base member and-a sixth gimbal frame pivoted lto said fth gimbal -frame on-a normally horizontal axisperpendicular to the pivotal axis of said fthgimbal v.fra-me, said sixth gimbal frame spanning said system and pivotally connected to the top offsaid second gimbal frame on the spin axis of said first gyroscope rotor.

`,iRliND WILLEM KUYVENHOVEN.

REFERENCES CITED The following references are `of record in :the le of this patent:

UNITED STATES PATENTS Knowles et al -J an. 14, 1947 

